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Democrituc
All matter consists of invisible particles called atoms.
2. Atoms are indestructible.
3. Atoms are solid but invisible.
4. Atoms are homogenous.
5. Atoms differ in size, shape, mass, position, and arrangement. -
Antoine Lavoisier
Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787)[3] and was also the first to establish that sulfur was an element (1777) rather than a compound.[4] He discovered that, although matter may chang -
John Dalton
Dalton created an Atomic Theory. It was: all matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms -
Invisible, Solid Sphere model
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Joseph Louis Proust
roust’s largest accomplishment into the realm of science was disproving Berthollet with the law of definite proportions, which is sometimes also known as Proust's Law. Proust studied copper carbonate, the two tin oxides, and the two iron sulfides to prove this law. He did this by making artificial copper carbonate and comparing it to natural copper carbonate -
Michael Faraday
discovered electromagnetic induction, the principle behind the electric transformer and generator. -
J.J. Thomson
Thomson showed that cathode rays were composed of a previously unknown negatively charged particle. He is credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle. Thomson is also credited with finding the first evidence for isotopes of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of canal rays (positive ions). He invented the mass spectrometer. -
Marie and Pierre Curie
Best known for their pioneering work in the study of radioactivity. They discovered the elements radium and polonium. -
Max Planck
onstant enabled him to define a new universal set of physical units (such as the Planck length and the Planck mass), all based on fundamental physical constants. Planck’s work on the quantum theory, as it came to be known, was published in the Annalen der Physik. His work is summarized in two books Thermodynamik (Thermodynamics) and Theorie der Wärmestrahlung (Theory of heat radiation). -
Ernest Rutherford
He is responsible for a remarkable series of discoveries in the fields of radioactivity and nuclear physics. He discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei. Most important, he postulated the nuclear structure of the atom. Also discovered the nucleus of an atom. -
Plum Pudding Model
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Albert Einstein
Explained the equivalency of mass and energy, expressed by the famous equation e=mc2. -
Robert Milikan
He discovered the charge of an electron. Millikan was able to show that the charge on a drop was always an integral multiple of a small, but finite value. The mass of an electron is at least 1000 times smaller than the lightest atom. -
Planetary Model
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Niels Bohr
Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
Quantum Mechanical Model
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Erwin Schrodinger
Developed a new model of the atom. He proposed that electrons are arranged in concentric circular orbits around the nucleus. This model is patterned on the solar system and is known as the planetary model -
Electron Cloud Model
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James Chadwick
Showed that in a reaction, a neutral particle with a mass about that of a proton, was emmitted. -
Lisa Meitner
first to recognize that the uranium atom, when bombarded by neutrons, actually split. -
Otto Hahn
Otto Hahn, OBE, ForMemRS was a German chemist and pioneer in the fields of radioactivity and radiochemistry who won the Nobel Prize in Chemistry in 1944 for the discovery of nuclear fission. -
Glenn T. Seaborg
Discovered transuranium elements. Identified more than 100 isotopes of elements through the periodic table. -
Louis De Broglie
The 1925's pilot-wave picture,[3] and the wave-like behaviour of particles discovered by de Broglie was used by Erwin Schrödinger in his formulation of wave mechanics;[4] but the pilot-wave model and interpretation was abandoned (in favor of quantum formalism) until 1952, when was rediscovered and enhanced by David Bohm.
Louis de Broglie was the sixteenth member elected to occupy seat 1 of the Académie française in 1944, and served as Perpetual Secretary of the French Academy of Sciences -
Henri Bequerel
Known for his discovery of spontaneous radioactivity -
Aristotle
He thought that all materials on Earth were not made of atoms, but of the four elements, Earth, Fire, Water, and Air. He believed all substances were made of small amounts of these four elements of matter.
